They are yokohamas if that matters on some pretty light ADR spiders. Also will they slow my car down a lot? Because you know we can't have that.hehe

 

they are the closest to the stock diameter. maybe +-1 or 2 mph.

 

Yeah, it shouldn't be off by much. At work, sometimes they put out one of those radar displays that show your speed to try to get people to drive slower on our roads. I've checked my speedometer against the radar so many times now. With my 215/40R16's the radar show 37mph when my speedo shows 40mpg. So the error's not that much even with my setup and your 205/45/R16's should be even closer.